[rabbitmq-discuss] Minor bug on the new erlang client

[Alvaro Videla]

Hi,

I was reading through the latest changes on the hg repo for the erlang client. 

I tried to build the docs to have a better understanding of the new modules but `make documentation` failed.

The problem is reported to be here http://hg.rabbitmq.com/rabbitmq-erlang-client/file/0247acc5c1d2/src/amqp_gen_consumer.erl#l33 with the _ character. 

I think is faster if I report it here than merging a diff that contains an `any()` instead of the `_`. Also maybe there's a better solution for edocs than the `any()`.

Cheers,

Alvaro